Sweetener composition

ABSTRACT

Herein is disclosed a sweetener composition containing Aspartame and Acesulfame-K as active ingredients, wherein the amount of Acesulfame-K is 5 to 90% by weight based on the total amount of both the components and wherein the particle sizes of the both the components are respectively selected from within the range of the particle size which allows the dissolution rate of the mixture to be higher than that of Aspartame alone, in which sweetener composition the poorly dissoluble, high intense synthetic sweetener Aspartame (APM) is improved in solubility.

TECHNICAL FIELD

The present invention relates to a highly soluble sweetener compositioncontaining Aspartame (hereinafter abbreviated as “APM”) and Acesulfame K(hereinafter abbreviated as “ACE-K”) as active ingredients.

BACKGROUND ART

It is reported that the level of sweetness of APM which is an aminoacid-based synthetic sweetener, is about 200 times that of sucrose interms of weight ratio (Japanese Patent Application Publication (Kokoku)No. 31031/'72). When compared with sucrose which is regarded as astandard for evaluating sweetness characteristics, the profile ofsweetness characteristics of APM is of such that it is weak in earlytaste (which means that the sweetener when placed in the mouth does nottaste sweet so early as sucrose does), whereas it is strong in latetaste (which means that the sweetener when placed in the mouth tastessweet later than sucrose does). Accordingly, various approaches for theimprovement of the sweetness profile of APM have been proposed mainly interms of the late taste (for example, Japanese Patent ApplicationLaid-open (Kokai) Nos. 148255/'81, 141760/'83, 220668/'83 and the like),and a method for obtaining a more natural sweetness profile which iscloser to that of sucrose, for example, by using APM in combination withsucrose has been also proposed (Japanese Patent Application Laid-open(Kokai) No. 152862/'82).

On the other hand, ACE-K is also a synthetic sweetener having asweetness level of about 200 times that of sucrose, like APM, but hassuch further poorer sweetness profile that it is strong in early taste,bitter taste, astringent taste, peculiar taste, and stimulation whencompared with APM. Therefore, it has been subjected to variousapproaches for the improvement, including the use in combination withAPM for improving the sweetness profile (U.S. Pat. No. 4,158,068, andcorresponding Japanese Patent Application Publication (Kokoku) No.51262/'84). For example, the Japanese Patent Application Publicationdiscloses the concurrent use of ACE-K and APM in a (weight) ratio ofabout 1:10 to 10:1, especially about 2:5 to 5:2, which, in turn,provides a sweetness profile closer to that of sucrose than that ofeither of the two.

Thus, various proposes have been made for improving the sweetnessprofile of APM, and each has been successful to some extent.Nevertheless, APM involves still such other problem concerning itssolubility characteristics that an industrially produced APM powder(original crystals) is difficult to dissolve in water (because it has atendency to form agglomerates (in Japanese, dama) and therefore, is notsmooth to dissolve, and even without that, it has a lower rate ofdissolution, and the like). The poorer solubility (i.e., poorerdissolution rate) due to such agglomeration and the like leads to thereduction in the production efficiency of food products or beverages tobe supplemented with APM for imparting sweetness thereto, including softdrinks, which is, in turn, greatly disadvantageous to the commercialproduction thereof.

Some approaches for improving the solubility of APM have been proposed,including a method of graining (granulation). However, these approachesare still not satisfactory, e.g., because the solubility needs furtherimproving (Japanese Patent Application Laid-open (Kokai) No. 346769/'92,and the like) and because a relatively larger amount of an excipientshould be used concomitantly (Japanese Patent Application Laid-open(Kokai) Nos. 126855/'74, 19965/'75, 150361/'82, and the like).Incidentally, the concurrent use of ACE-K with APM disclosed in theabove-mentioned Japanese Patent Application Publication (Kokoku) No.51262/'84 is a concurrent use by merely mixing aqueous solutions of thetwo components (i.e., an aqueous ACE-K solution and an aqueous APMsolution), and there is not made in the patent document any suggestionof the concurrent use of the two components, both in the form oforiginal crystals or granules, nor any mention of the solubility ofeither of the two in the original crystals or granular form.

In view of the prior art discussed above, it is an object of the presentinvention to provide an excellent method for improving the solubility ofAPM.

DISCLOSURE OF THE INVENTION

The present inventors have made an effort to achieve the objectdescribed above and found unexpectedly that, in the presence ofuntreated crystals of ACE-K or a product resulting from pulverizing theuntreated crystals (hereinafter abbreviated as “pulverized ACE-K”),untreated crystals or granules of APM undergo no agglomeration duringdissolution (in water) and exhibit a higher dissolution rate as comparedwith the case of APM alone, i.e., that APM is on the whole improved insolubility, thus establishing the present invention.

Accordingly, the present invention relates to a sweetener compositioncomprising Aspartame and Acesulfame-K as active ingredients, wherein theamount of Acesulfame-K is 5 to 90% by weight based on the total amountof both the components and wherein the particle sizes of both thecomponents are respectively selected from within the range of theparticle size which allows the dissolution rate of the mixture to behigher than that of Aspartame alone.

The present invention will be further described in greater detail below.

APM, which is one of the active ingredients of a sweetener compositionof the present invention, can be a commercially available untreatedcrystalline powder (untreated crystals) as it is or granules having alarger particle size made by granulating such untreated powder. While itis known that APM is imparted with an improved solubility when it isgranulated (Japanese Patent Application Laid-Open (Kokai) No.346769/'92, described above), it has been found by the present inventorsthat the solubility of such granules can be further improved in thepresence of ACE-K. Furthermore, it has been found that APM can be stillimparted with a higher solubility in the presence of ACE-K also when itis in the form of untreated crystals.

Granules of APM can be produced by granulating an APM originalcrystalline powder. The granulation is not particularly limited, and canbe conducted in accordance with a known method. For example, a drygranulating process and also a wet granulating process can be employed.Specifically, granules can be produced by various methods such as mixinggranulation, compacting granulation, extrusion granulation, fluidizationgranulation, rotation granulation, pulverization granulation, spraycoating, tabletting or the like. However, for the purpose of less heatload and less complicated manufacturing process, it is commerciallyadvantageous to employ a dry granulation process such as compactinggranulation.

ACE-K which is the other active ingredient of a sweetener composition ofthe present invention can be incorporated in the sweetener compositionas untreated crystals as they are or after being pulverized (i.e., inthe pulverized form).

An untreated crystalline powder of ACE-K can be prepared by a knownmethod and converted into one having a desired particle size by means ofcrystallization and, if necessary, pulverization.

The mixing ratio (ratio of amounts employed) of APM and ACE-K in asweetening composition of the present invention is appropriate when theACE-K is present in an amount of 5 to 90% by weight based on the totalamount of both the components. Incidentally, an ACE-K content of 5% byweight or less provides almost no dissolution-promoting effect by ACE-K,while that of 90% by weight or higher causes the bitter taste of theACE-K to get evident, which is of course undesirable.

Even with a mixing ratio between APM and ACE-K specified above, thedissolution-promoting effect by ACE-K on APM varies depending on theparticle sizes of APM (untreated crystalline powder or granule) andACE-K (untreated crystalline powder or pulverized product). Too smallparticle size of APM may cause formation of agglomerates (in Japanese,dama) and may cause the APM to float on the surface of water instead ofbeing dispersed in water, which may, in turn, take a prolonged timeperiod for dissolution, while a too large particle size of the granulesmay result in a reduction of the interface area where the particles andthe water are in contact, which may, in turn, take a prolonged timeperiod for dissolution. APM to float on the surface of water instead ofbeing dispersed in water, which may, in turn, take a prolonged timeperiod for dissolution, while too a large particle size of the granulesmay result in a reduction in the interface area where the particles andthe water are in contact, which may, in turn, take a prolonged timeperiod for dissolution.

An improvement in the solubility of APM as a result of admixing ACE-K isdue to the prevention thereby of the agglomeration of APM and theprevention thereby of the floating of APM on the surface of water, and amore thorough mixing of both the components provides a higher effect. Ahigher effect is obtained with a smaller particle size of ACE-K since amore thorough mixing is possible. ACE-K whose true specific gravity is1.85 (in contrast to 1.36 of APM) exhibits a satisfactory sedimentation,and its high solubility allows fine particles, which tend to float, tobe readily dissolved and disappear. Incorporation of ACE-K also reducesthe floating of APM on the liquid surface. A higher effect by a smallerparticle size of APM is due not only to a more thorough mixing but alsoto the prevention of the agglomeration and the prevention of thefloating on the liquid surface, and to the fact that larger particleslimit the dissolution rate.

As has been described above, ACE-K exhibits a higherdissolution-improving effect on APM when its particle size is smaller,and the average particle size is preferably about 250 μm or less. Themaximum particle size is preferably about 500 μm or less, and morepreferably about 250 μm or less. ACE-K having such a small particle sizecan be readily prepared by pulverizing an ACE-K untreated crystallinepowder by a known appropriate method. While APM exhibits a highersolubility when it is in the granule form than when it is in theuntreated crystalline powder, an excessively large particle size poses aprolonged time period required for dissolution as described above, andthe average particle size is preferably about 500 μm or less.

In a given case, the particle size of ACE-K which exerts a markeddissolution-promoting effect on APM can be determined as a particle sizeof ACE-K in the admixture with which a given untreated crystallinepowder (untreated crystals) or given granules of APM can exhibit asignificantly improved dissolution rate (time period required fordissolution) as compared with the dissolution rate of the same APMuntreated crystalline powder (untreated crystals) in the same quantityas contained in the above mixture when tested alone (see Experiment 1,last paragraph, described below). It is a matter of course that suchparticle size of ACE-K for a given APM untreated crystals can be readilydetermined by those skilled in the art by performing a preliminary test.

Incidentally, when APM and ACE-K having inventive particle sizes areplaced in water separately but simultaneously (separate addition)without mixing previously at an inventive ratio (as in the case of aninventive sweetening composition), ACE-K having a high dissolution ratedissolves rapidly and prevents the dissolution rate of APM from beingdependent on the particle size of ACE-K, resulting in the dissolutionrate of APM as a sole component (Experiment 3 described below).

The inventive sweetener composition can, depending on its use, contain adiluent or an excipient such as a sugar alcohol, an oligosaccharide anda dietary fiber as well as other high intense synthetic sweetener(s)such as Alitame, Saccharin, 3,3-dimethylbutylaspartylphenylalaninemethylester and the like, like in the case of conventional intensesynthetic sweetener compositions, for the purpose of obtaining a betterhandling or improving the sweetness profile, as long as the improvedsolubility of APM according to the present invention is not affectedadversely. A diluent or an excipient referred to herein includes a lowintense sweetener such as sucrose, glucose and the like.

The solubility of APM granules (i.e., granules consisting of APM alone)as disclosed in the above-mentioned Japanese Patent ApplicationLaid-open (Kokai) No. 346769/'92, is just less unsatisfactory than thatof an APM original powder, and further improvement of the solubility isdemanded by users. In accordance with the present invention, suchfurther improvement of the solubility of APM has been realized, and alsoan excellent sweetener can be produced in which the sweetness profilesof both of APM and ACE-K are improved.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be further described with reference to thefollowing Experiments.

Experiment 1

(Solubility of Mixture of APM Untreated Powder and ACE-K UntreatedPowder)

A 1 L dissolution tester (the Japanese Pharmacopoeia, Paddle method(container of 100 mm in inner size, 160 mm in height, having ahemispheric bottom of 50 mm in radius, and a net volume of 1,000 ml;paddle formed by sectioning a disc of 83 mm in size, and 3 mm inthickness, with parallel strings of 42 mm and 75 mm in length; 25 mm indistance between the lower end thereof and the container bottom), 100rpm) was used together with 900 ml of water (20° C.), in which a samplewas placed in a predetermined amount and examined for the time periodrequired for dissolution (the endpoint being judged visually).

In greater detail, an APM untreated crystalline powder (average particlesize being about 15 μm, and maximum particle size being about 100 μm;IB-type bundle-like crystals) and an ACE-K untreated crystalline powder(average particle size being about 250 μm, and maximum particle sizebeing about 500 μm) were mixed in a varying ratio indicated (in terms of% by weight of ACE-K) in Table 1 shown below to prepare mixtures. 1 gpotion was taken from each mixture and examined for the time periodrequired for dissolution. For comparison, 1 g of the APM untreatedpowder described above was also examined for the time period requiredfor dissolution. For reference, 0.5 g and 0.10 g of the APM untreatedpowder were also examined for the time periods required for dissolution.

The samples exhibited their respective time periods (min) required fordissolution indicated in Table 1 shown below.

TABLE 1 Time period (min) for dissolution of mixture of APM untreatedpowder and ACE-K untreated powder Mixture (1 g) % By weight of ACE-Kuntreated APM alone powder (APM untreated powder) (untreated powder) 5%20% 50% 90% Sample 1.00 g 0.50 g 0.10 g (0.95 g) (0.80 g) (0.50 g) (0.10g) Dissolution 30 20 10 15 11 6 4 time (min)

As is evident from the table shown above, the solubility of the mixtures(inventive sweetener compositons) was improved markedly as compared withthe APM untreated crystalline powder.

Incidentally, the sweetness level of both APM and ACE-K is about 200times that of sucrose as described above. Accordingly, the amount of asample of an APM untreated powder alone which should be compared in timeperiod required for dissolution with 1 g of a mixture sample is 1 gwhich is the same amount of the mixture sample because such time periodcan be regarded as the time period required for obtaining the samesweetness. Nevertheless, the results obtained when 0.5 g and 0.1 g of asample consisting only of an APM untreated powder were determined justfor reference revealed that ACE-K has the dissolution-promoting effecton APM.

Experiment 2

(Solubility of Mixtures of APM having a Varying Particle Size andPulverized ACE-K)

The time period for dissolution of a mixture of an APM having a varyingparticle size (untreated powder or granules) and a pulverized ACE-K wasdetermined in the same manner as in Experiment 1.

The APM untreated powder employed was the same untreated powder asemployed in Experiment 1 (average particle size being about 15 μm, andmaximum particle size being about 100 μm or less). The untreated powderwas granulated using a dry rol mill (dry compaction and disintegration),and sieved to obtain fractions having a varying particle size.Specifically, the dry compaction and dry disintegration were performedusing a compacting machine “ROLLER COMPACTER Model WP90 X 30” (ex TURBOKOGYO), and the mixture was, upon compaction, fed to the compactingmachine via a screw feeder (88 rpm) under a roll pressure of 4.9 Mpa ata roll speed of 12 rpm, and then disintegrated using a fine granulatorscreen of 12 mesh size (pore size being 1,400 μm). The granules weresieved using a JIS (Japanese Industrial Standard) standard sieve.

A pulverized ACE-K employed was that prepared by pulverizing the sameACE-K as employed in Experiment 1 (average particle size being about 250μm, and maximum particle size being about 500 μm) by a compactlaboratory centrifugal pulverizer (250 μm φ screen; 20,000 rpm) toobtain a pulverized ACE-K whose average particle size was about 20 μmand whose maximum particle size was about 250 μm.

The sample amount of a mixture and the sample amount of APM alone(untreated powder or granules of APM alone) were the same as inExperiment 1.

The time period (min) required for dissolution of each sample isindicated in Table 2 shown below.

TABLE 2 Time period (min) required for dissolution of a mixture of APMuntreated powder or granules and pulverized ACB-K Mixture (1 g)Pulverized ACB-K APM alone (APM untreated powder or granules) (untreatedpowder or granules) 5% 20% 50% 90% Sample Particle size 1.00 g 0.50 g0.10 g (0.95 g) (0.80 g) (0.50 g) (0.10 g) Dissolution to 100 μm(Untreated 30 20 10 5 3 3 3 time (min) powder) 100 to 300 μm (Granules)18 17 7 9 — 5 — 300 to 500 μm (Granules) 18 17 7 12 — 8 —

As is evident from Table 2 shown above, APM can be improved markedly insolubility by ACE-k, at various particle sizes.

Experiment 3

(Separate Addition of APM Untreated Powder and Pulverized ACE-K)

The same APM untreated powder as employed in Experiment 1 (averageparticle size being about 15 μm, and maximum particle size being about100 μm) and the same pulverized ACE-K as employed in Experiment 2(average particle size being about 20 μm and maximum particle size beingabout 250 μm) were examined for the time periods required fordissolution in the same manner as in Experiment 1.

Thus, 0.5 g of each of both the components were taken (1.0 g in total)and added to the dissolution tester simultaneously without admixingpreviously (separate addition). The results are indicated in Table 3shown below. Just for reference, the time period required fordissolution of 0.5 g of the APM untreated powder alone (experiment 1) isalso indicated.

TABLE 3 Time period (min) required for dissolution of APM and ACE-Kadded separately and simultaneously APM alone Separate addition (1 g intotal) (untreated powder) (0.5 g APM untreated powder/0.5 g Sample (0.5g) pulverized ACE-K) Dissolution 20 20 time (min)

As is evident from Table 3 shown above, no solubility-improving effectby ACE-K on APM was observed when APM and ACE-K were added separatelywithout admixing previously. This is because of an extremely rapiddissolution of ACE-K as described above.

INDUSTRIAL APPLICABILITY

By mixing an untreated powder or granules of Aspartame (APM) and anuntreated crystalline powder or a pulverized product of Acesulfame-K(ACE-K) according to the present invention, the poor solubility (i.e.,poor dissolution rate) of APM can be improved markedly, and a sweetenerhaving an excellent sweetness profile can readily be prepared.

We claim:
 1. A sweetener composition comprising a mixture of untreated crystalline powder or granules of Aspartame and untreated crystalline powder or pulverized product of Acesulfame-K, wherein the amount of Acesulfame-K is 5 to 90% by weight based on the total amount of both components and wherein the particle sizes of both components are respectively selected from within a range of the particle size which provide a dissolution rate of the mixture higher than that of the Aspartame particles alone.
 2. The sweetener composition according to claim 1, wherein the average particle size of said Acesulfame-K is about 250 μm or less.
 3. The sweetener composition according to claim 1, wherein the maximum particle size of said Acesulfame-K is about 250 μm or less.
 4. The sweetener composition according to claim 1, wherein the average particle size of said Aspartame is about 500 μm or less.
 5. The sweetener composition according to claim 2, wherein the average particle size of said aspartame is about 500 μm or less.
 6. The sweetener composition according to claim 3, wherein the average particle size of said aspartame is about 500 μm or less. 